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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network244.255.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
244.255.0.0
Broadcast address
244.255.31.255
First usable
244.255.0.1
Last usable
244.255.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F4FF0000 · Integer 4110352384 to 4110360575
Reverse DNS zones
0.255.244.in-addr.arpa
1.255.244.in-addr.arpa
2.255.244.in-addr.arpa
3.255.244.in-addr.arpa
4.255.244.in-addr.arpa
5.255.244.in-addr.arpa
6.255.244.in-addr.arpa
7.255.244.in-addr.arpa
8.255.244.in-addr.arpa
9.255.244.in-addr.arpa
10.255.244.in-addr.arpa
11.255.244.in-addr.arpa
12.255.244.in-addr.arpa
13.255.244.in-addr.arpa
14.255.244.in-addr.arpa
15.255.244.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110100.11111111.00000000.00000000244.255.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11110100.11111111.00000000.00000000244.255.0.0
Broadcast11110100.11111111.00011111.11111111244.255.31.255
Split into smaller subnets/27
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

244.255.0.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1244.255.0.0/27244.255.0.1 to 244.255.0.30244.255.0.3130
2244.255.0.32/27244.255.0.33 to 244.255.0.62244.255.0.6330
3244.255.0.64/27244.255.0.65 to 244.255.0.94244.255.0.9530
4244.255.0.96/27244.255.0.97 to 244.255.0.126244.255.0.12730
5244.255.0.128/27244.255.0.129 to 244.255.0.158244.255.0.15930
6244.255.0.160/27244.255.0.161 to 244.255.0.190244.255.0.19130
7244.255.0.192/27244.255.0.193 to 244.255.0.222244.255.0.22330
8244.255.0.224/27244.255.0.225 to 244.255.0.254244.255.0.25530
9244.255.1.0/27244.255.1.1 to 244.255.1.30244.255.1.3130
10244.255.1.32/27244.255.1.33 to 244.255.1.62244.255.1.6330
11244.255.1.64/27244.255.1.65 to 244.255.1.94244.255.1.9530
12244.255.1.96/27244.255.1.97 to 244.255.1.126244.255.1.12730
13244.255.1.128/27244.255.1.129 to 244.255.1.158244.255.1.15930
14244.255.1.160/27244.255.1.161 to 244.255.1.190244.255.1.19130
15244.255.1.192/27244.255.1.193 to 244.255.1.222244.255.1.22330
16244.255.1.224/27244.255.1.225 to 244.255.1.254244.255.1.25530
17244.255.2.0/27244.255.2.1 to 244.255.2.30244.255.2.3130
18244.255.2.32/27244.255.2.33 to 244.255.2.62244.255.2.6330
19244.255.2.64/27244.255.2.65 to 244.255.2.94244.255.2.9530
20244.255.2.96/27244.255.2.97 to 244.255.2.126244.255.2.12730
21244.255.2.128/27244.255.2.129 to 244.255.2.158244.255.2.15930
22244.255.2.160/27244.255.2.161 to 244.255.2.190244.255.2.19130
23244.255.2.192/27244.255.2.193 to 244.255.2.222244.255.2.22330
24244.255.2.224/27244.255.2.225 to 244.255.2.254244.255.2.25530
25244.255.3.0/27244.255.3.1 to 244.255.3.30244.255.3.3130
26244.255.3.32/27244.255.3.33 to 244.255.3.62244.255.3.6330
27244.255.3.64/27244.255.3.65 to 244.255.3.94244.255.3.9530
28244.255.3.96/27244.255.3.97 to 244.255.3.126244.255.3.12730
29244.255.3.128/27244.255.3.129 to 244.255.3.158244.255.3.15930
30244.255.3.160/27244.255.3.161 to 244.255.3.190244.255.3.19130
31244.255.3.192/27244.255.3.193 to 244.255.3.222244.255.3.22330
32244.255.3.224/27244.255.3.225 to 244.255.3.254244.255.3.25530
33244.255.4.0/27244.255.4.1 to 244.255.4.30244.255.4.3130
34244.255.4.32/27244.255.4.33 to 244.255.4.62244.255.4.6330
35244.255.4.64/27244.255.4.65 to 244.255.4.94244.255.4.9530
36244.255.4.96/27244.255.4.97 to 244.255.4.126244.255.4.12730
37244.255.4.128/27244.255.4.129 to 244.255.4.158244.255.4.15930
38244.255.4.160/27244.255.4.161 to 244.255.4.190244.255.4.19130
39244.255.4.192/27244.255.4.193 to 244.255.4.222244.255.4.22330
40244.255.4.224/27244.255.4.225 to 244.255.4.254244.255.4.25530
41244.255.5.0/27244.255.5.1 to 244.255.5.30244.255.5.3130
42244.255.5.32/27244.255.5.33 to 244.255.5.62244.255.5.6330
43244.255.5.64/27244.255.5.65 to 244.255.5.94244.255.5.9530
44244.255.5.96/27244.255.5.97 to 244.255.5.126244.255.5.12730
45244.255.5.128/27244.255.5.129 to 244.255.5.158244.255.5.15930
46244.255.5.160/27244.255.5.161 to 244.255.5.190244.255.5.19130
47244.255.5.192/27244.255.5.193 to 244.255.5.222244.255.5.22330
48244.255.5.224/27244.255.5.225 to 244.255.5.254244.255.5.25530
49244.255.6.0/27244.255.6.1 to 244.255.6.30244.255.6.3130
50244.255.6.32/27244.255.6.33 to 244.255.6.62244.255.6.6330
51244.255.6.64/27244.255.6.65 to 244.255.6.94244.255.6.9530
52244.255.6.96/27244.255.6.97 to 244.255.6.126244.255.6.12730
53244.255.6.128/27244.255.6.129 to 244.255.6.158244.255.6.15930
54244.255.6.160/27244.255.6.161 to 244.255.6.190244.255.6.19130
55244.255.6.192/27244.255.6.193 to 244.255.6.222244.255.6.22330
56244.255.6.224/27244.255.6.225 to 244.255.6.254244.255.6.25530
57244.255.7.0/27244.255.7.1 to 244.255.7.30244.255.7.3130
58244.255.7.32/27244.255.7.33 to 244.255.7.62244.255.7.6330
59244.255.7.64/27244.255.7.65 to 244.255.7.94244.255.7.9530
60244.255.7.96/27244.255.7.97 to 244.255.7.126244.255.7.12730
61244.255.7.128/27244.255.7.129 to 244.255.7.158244.255.7.15930
62244.255.7.160/27244.255.7.161 to 244.255.7.190244.255.7.19130
63244.255.7.192/27244.255.7.193 to 244.255.7.222244.255.7.22330
64244.255.7.224/27244.255.7.225 to 244.255.7.254244.255.7.25530
65244.255.8.0/27244.255.8.1 to 244.255.8.30244.255.8.3130
66244.255.8.32/27244.255.8.33 to 244.255.8.62244.255.8.6330
67244.255.8.64/27244.255.8.65 to 244.255.8.94244.255.8.9530
68244.255.8.96/27244.255.8.97 to 244.255.8.126244.255.8.12730
69244.255.8.128/27244.255.8.129 to 244.255.8.158244.255.8.15930
70244.255.8.160/27244.255.8.161 to 244.255.8.190244.255.8.19130
71244.255.8.192/27244.255.8.193 to 244.255.8.222244.255.8.22330
72244.255.8.224/27244.255.8.225 to 244.255.8.254244.255.8.25530
73244.255.9.0/27244.255.9.1 to 244.255.9.30244.255.9.3130
74244.255.9.32/27244.255.9.33 to 244.255.9.62244.255.9.6330
75244.255.9.64/27244.255.9.65 to 244.255.9.94244.255.9.9530
76244.255.9.96/27244.255.9.97 to 244.255.9.126244.255.9.12730
77244.255.9.128/27244.255.9.129 to 244.255.9.158244.255.9.15930
78244.255.9.160/27244.255.9.161 to 244.255.9.190244.255.9.19130
79244.255.9.192/27244.255.9.193 to 244.255.9.222244.255.9.22330
80244.255.9.224/27244.255.9.225 to 244.255.9.254244.255.9.25530
81244.255.10.0/27244.255.10.1 to 244.255.10.30244.255.10.3130
82244.255.10.32/27244.255.10.33 to 244.255.10.62244.255.10.6330
83244.255.10.64/27244.255.10.65 to 244.255.10.94244.255.10.9530
84244.255.10.96/27244.255.10.97 to 244.255.10.126244.255.10.12730
85244.255.10.128/27244.255.10.129 to 244.255.10.158244.255.10.15930
86244.255.10.160/27244.255.10.161 to 244.255.10.190244.255.10.19130
87244.255.10.192/27244.255.10.193 to 244.255.10.222244.255.10.22330
88244.255.10.224/27244.255.10.225 to 244.255.10.254244.255.10.25530
89244.255.11.0/27244.255.11.1 to 244.255.11.30244.255.11.3130
90244.255.11.32/27244.255.11.33 to 244.255.11.62244.255.11.6330
91244.255.11.64/27244.255.11.65 to 244.255.11.94244.255.11.9530
92244.255.11.96/27244.255.11.97 to 244.255.11.126244.255.11.12730
93244.255.11.128/27244.255.11.129 to 244.255.11.158244.255.11.15930
94244.255.11.160/27244.255.11.161 to 244.255.11.190244.255.11.19130
95244.255.11.192/27244.255.11.193 to 244.255.11.222244.255.11.22330
96244.255.11.224/27244.255.11.225 to 244.255.11.254244.255.11.25530
97244.255.12.0/27244.255.12.1 to 244.255.12.30244.255.12.3130
98244.255.12.32/27244.255.12.33 to 244.255.12.62244.255.12.6330
99244.255.12.64/27244.255.12.65 to 244.255.12.94244.255.12.9530
100244.255.12.96/27244.255.12.97 to 244.255.12.126244.255.12.12730
101244.255.12.128/27244.255.12.129 to 244.255.12.158244.255.12.15930
102244.255.12.160/27244.255.12.161 to 244.255.12.190244.255.12.19130
103244.255.12.192/27244.255.12.193 to 244.255.12.222244.255.12.22330
104244.255.12.224/27244.255.12.225 to 244.255.12.254244.255.12.25530
105244.255.13.0/27244.255.13.1 to 244.255.13.30244.255.13.3130
106244.255.13.32/27244.255.13.33 to 244.255.13.62244.255.13.6330
107244.255.13.64/27244.255.13.65 to 244.255.13.94244.255.13.9530
108244.255.13.96/27244.255.13.97 to 244.255.13.126244.255.13.12730
109244.255.13.128/27244.255.13.129 to 244.255.13.158244.255.13.15930
110244.255.13.160/27244.255.13.161 to 244.255.13.190244.255.13.19130
111244.255.13.192/27244.255.13.193 to 244.255.13.222244.255.13.22330
112244.255.13.224/27244.255.13.225 to 244.255.13.254244.255.13.25530
113244.255.14.0/27244.255.14.1 to 244.255.14.30244.255.14.3130
114244.255.14.32/27244.255.14.33 to 244.255.14.62244.255.14.6330
115244.255.14.64/27244.255.14.65 to 244.255.14.94244.255.14.9530
116244.255.14.96/27244.255.14.97 to 244.255.14.126244.255.14.12730
117244.255.14.128/27244.255.14.129 to 244.255.14.158244.255.14.15930
118244.255.14.160/27244.255.14.161 to 244.255.14.190244.255.14.19130
119244.255.14.192/27244.255.14.193 to 244.255.14.222244.255.14.22330
120244.255.14.224/27244.255.14.225 to 244.255.14.254244.255.14.25530
121244.255.15.0/27244.255.15.1 to 244.255.15.30244.255.15.3130
122244.255.15.32/27244.255.15.33 to 244.255.15.62244.255.15.6330
123244.255.15.64/27244.255.15.65 to 244.255.15.94244.255.15.9530
124244.255.15.96/27244.255.15.97 to 244.255.15.126244.255.15.12730
125244.255.15.128/27244.255.15.129 to 244.255.15.158244.255.15.15930
126244.255.15.160/27244.255.15.161 to 244.255.15.190244.255.15.19130
127244.255.15.192/27244.255.15.193 to 244.255.15.222244.255.15.22330
128244.255.15.224/27244.255.15.225 to 244.255.15.254244.255.15.25530
129244.255.16.0/27244.255.16.1 to 244.255.16.30244.255.16.3130
130244.255.16.32/27244.255.16.33 to 244.255.16.62244.255.16.6330
131244.255.16.64/27244.255.16.65 to 244.255.16.94244.255.16.9530
132244.255.16.96/27244.255.16.97 to 244.255.16.126244.255.16.12730
133244.255.16.128/27244.255.16.129 to 244.255.16.158244.255.16.15930
134244.255.16.160/27244.255.16.161 to 244.255.16.190244.255.16.19130
135244.255.16.192/27244.255.16.193 to 244.255.16.222244.255.16.22330
136244.255.16.224/27244.255.16.225 to 244.255.16.254244.255.16.25530
137244.255.17.0/27244.255.17.1 to 244.255.17.30244.255.17.3130
138244.255.17.32/27244.255.17.33 to 244.255.17.62244.255.17.6330
139244.255.17.64/27244.255.17.65 to 244.255.17.94244.255.17.9530
140244.255.17.96/27244.255.17.97 to 244.255.17.126244.255.17.12730
141244.255.17.128/27244.255.17.129 to 244.255.17.158244.255.17.15930
142244.255.17.160/27244.255.17.161 to 244.255.17.190244.255.17.19130
143244.255.17.192/27244.255.17.193 to 244.255.17.222244.255.17.22330
144244.255.17.224/27244.255.17.225 to 244.255.17.254244.255.17.25530
145244.255.18.0/27244.255.18.1 to 244.255.18.30244.255.18.3130
146244.255.18.32/27244.255.18.33 to 244.255.18.62244.255.18.6330
147244.255.18.64/27244.255.18.65 to 244.255.18.94244.255.18.9530
148244.255.18.96/27244.255.18.97 to 244.255.18.126244.255.18.12730
149244.255.18.128/27244.255.18.129 to 244.255.18.158244.255.18.15930
150244.255.18.160/27244.255.18.161 to 244.255.18.190244.255.18.19130
151244.255.18.192/27244.255.18.193 to 244.255.18.222244.255.18.22330
152244.255.18.224/27244.255.18.225 to 244.255.18.254244.255.18.25530
153244.255.19.0/27244.255.19.1 to 244.255.19.30244.255.19.3130
154244.255.19.32/27244.255.19.33 to 244.255.19.62244.255.19.6330
155244.255.19.64/27244.255.19.65 to 244.255.19.94244.255.19.9530
156244.255.19.96/27244.255.19.97 to 244.255.19.126244.255.19.12730
157244.255.19.128/27244.255.19.129 to 244.255.19.158244.255.19.15930
158244.255.19.160/27244.255.19.161 to 244.255.19.190244.255.19.19130
159244.255.19.192/27244.255.19.193 to 244.255.19.222244.255.19.22330
160244.255.19.224/27244.255.19.225 to 244.255.19.254244.255.19.25530
161244.255.20.0/27244.255.20.1 to 244.255.20.30244.255.20.3130
162244.255.20.32/27244.255.20.33 to 244.255.20.62244.255.20.6330
163244.255.20.64/27244.255.20.65 to 244.255.20.94244.255.20.9530
164244.255.20.96/27244.255.20.97 to 244.255.20.126244.255.20.12730
165244.255.20.128/27244.255.20.129 to 244.255.20.158244.255.20.15930
166244.255.20.160/27244.255.20.161 to 244.255.20.190244.255.20.19130
167244.255.20.192/27244.255.20.193 to 244.255.20.222244.255.20.22330
168244.255.20.224/27244.255.20.225 to 244.255.20.254244.255.20.25530
169244.255.21.0/27244.255.21.1 to 244.255.21.30244.255.21.3130
170244.255.21.32/27244.255.21.33 to 244.255.21.62244.255.21.6330
171244.255.21.64/27244.255.21.65 to 244.255.21.94244.255.21.9530
172244.255.21.96/27244.255.21.97 to 244.255.21.126244.255.21.12730
173244.255.21.128/27244.255.21.129 to 244.255.21.158244.255.21.15930
174244.255.21.160/27244.255.21.161 to 244.255.21.190244.255.21.19130
175244.255.21.192/27244.255.21.193 to 244.255.21.222244.255.21.22330
176244.255.21.224/27244.255.21.225 to 244.255.21.254244.255.21.25530
177244.255.22.0/27244.255.22.1 to 244.255.22.30244.255.22.3130
178244.255.22.32/27244.255.22.33 to 244.255.22.62244.255.22.6330
179244.255.22.64/27244.255.22.65 to 244.255.22.94244.255.22.9530
180244.255.22.96/27244.255.22.97 to 244.255.22.126244.255.22.12730
181244.255.22.128/27244.255.22.129 to 244.255.22.158244.255.22.15930
182244.255.22.160/27244.255.22.161 to 244.255.22.190244.255.22.19130
183244.255.22.192/27244.255.22.193 to 244.255.22.222244.255.22.22330
184244.255.22.224/27244.255.22.225 to 244.255.22.254244.255.22.25530
185244.255.23.0/27244.255.23.1 to 244.255.23.30244.255.23.3130
186244.255.23.32/27244.255.23.33 to 244.255.23.62244.255.23.6330
187244.255.23.64/27244.255.23.65 to 244.255.23.94244.255.23.9530
188244.255.23.96/27244.255.23.97 to 244.255.23.126244.255.23.12730
189244.255.23.128/27244.255.23.129 to 244.255.23.158244.255.23.15930
190244.255.23.160/27244.255.23.161 to 244.255.23.190244.255.23.19130
191244.255.23.192/27244.255.23.193 to 244.255.23.222244.255.23.22330
192244.255.23.224/27244.255.23.225 to 244.255.23.254244.255.23.25530
193244.255.24.0/27244.255.24.1 to 244.255.24.30244.255.24.3130
194244.255.24.32/27244.255.24.33 to 244.255.24.62244.255.24.6330
195244.255.24.64/27244.255.24.65 to 244.255.24.94244.255.24.9530
196244.255.24.96/27244.255.24.97 to 244.255.24.126244.255.24.12730
197244.255.24.128/27244.255.24.129 to 244.255.24.158244.255.24.15930
198244.255.24.160/27244.255.24.161 to 244.255.24.190244.255.24.19130
199244.255.24.192/27244.255.24.193 to 244.255.24.222244.255.24.22330
200244.255.24.224/27244.255.24.225 to 244.255.24.254244.255.24.25530
201244.255.25.0/27244.255.25.1 to 244.255.25.30244.255.25.3130
202244.255.25.32/27244.255.25.33 to 244.255.25.62244.255.25.6330
203244.255.25.64/27244.255.25.65 to 244.255.25.94244.255.25.9530
204244.255.25.96/27244.255.25.97 to 244.255.25.126244.255.25.12730
205244.255.25.128/27244.255.25.129 to 244.255.25.158244.255.25.15930
206244.255.25.160/27244.255.25.161 to 244.255.25.190244.255.25.19130
207244.255.25.192/27244.255.25.193 to 244.255.25.222244.255.25.22330
208244.255.25.224/27244.255.25.225 to 244.255.25.254244.255.25.25530
209244.255.26.0/27244.255.26.1 to 244.255.26.30244.255.26.3130
210244.255.26.32/27244.255.26.33 to 244.255.26.62244.255.26.6330
211244.255.26.64/27244.255.26.65 to 244.255.26.94244.255.26.9530
212244.255.26.96/27244.255.26.97 to 244.255.26.126244.255.26.12730
213244.255.26.128/27244.255.26.129 to 244.255.26.158244.255.26.15930
214244.255.26.160/27244.255.26.161 to 244.255.26.190244.255.26.19130
215244.255.26.192/27244.255.26.193 to 244.255.26.222244.255.26.22330
216244.255.26.224/27244.255.26.225 to 244.255.26.254244.255.26.25530
217244.255.27.0/27244.255.27.1 to 244.255.27.30244.255.27.3130
218244.255.27.32/27244.255.27.33 to 244.255.27.62244.255.27.6330
219244.255.27.64/27244.255.27.65 to 244.255.27.94244.255.27.9530
220244.255.27.96/27244.255.27.97 to 244.255.27.126244.255.27.12730
221244.255.27.128/27244.255.27.129 to 244.255.27.158244.255.27.15930
222244.255.27.160/27244.255.27.161 to 244.255.27.190244.255.27.19130
223244.255.27.192/27244.255.27.193 to 244.255.27.222244.255.27.22330
224244.255.27.224/27244.255.27.225 to 244.255.27.254244.255.27.25530
225244.255.28.0/27244.255.28.1 to 244.255.28.30244.255.28.3130
226244.255.28.32/27244.255.28.33 to 244.255.28.62244.255.28.6330
227244.255.28.64/27244.255.28.65 to 244.255.28.94244.255.28.9530
228244.255.28.96/27244.255.28.97 to 244.255.28.126244.255.28.12730
229244.255.28.128/27244.255.28.129 to 244.255.28.158244.255.28.15930
230244.255.28.160/27244.255.28.161 to 244.255.28.190244.255.28.19130
231244.255.28.192/27244.255.28.193 to 244.255.28.222244.255.28.22330
232244.255.28.224/27244.255.28.225 to 244.255.28.254244.255.28.25530
233244.255.29.0/27244.255.29.1 to 244.255.29.30244.255.29.3130
234244.255.29.32/27244.255.29.33 to 244.255.29.62244.255.29.6330
235244.255.29.64/27244.255.29.65 to 244.255.29.94244.255.29.9530
236244.255.29.96/27244.255.29.97 to 244.255.29.126244.255.29.12730
237244.255.29.128/27244.255.29.129 to 244.255.29.158244.255.29.15930
238244.255.29.160/27244.255.29.161 to 244.255.29.190244.255.29.19130
239244.255.29.192/27244.255.29.193 to 244.255.29.222244.255.29.22330
240244.255.29.224/27244.255.29.225 to 244.255.29.254244.255.29.25530
241244.255.30.0/27244.255.30.1 to 244.255.30.30244.255.30.3130
242244.255.30.32/27244.255.30.33 to 244.255.30.62244.255.30.6330
243244.255.30.64/27244.255.30.65 to 244.255.30.94244.255.30.9530
244244.255.30.96/27244.255.30.97 to 244.255.30.126244.255.30.12730
245244.255.30.128/27244.255.30.129 to 244.255.30.158244.255.30.15930
246244.255.30.160/27244.255.30.161 to 244.255.30.190244.255.30.19130
247244.255.30.192/27244.255.30.193 to 244.255.30.222244.255.30.22330
248244.255.30.224/27244.255.30.225 to 244.255.30.254244.255.30.25530
249244.255.31.0/27244.255.31.1 to 244.255.31.30244.255.31.3130
250244.255.31.32/27244.255.31.33 to 244.255.31.62244.255.31.6330
251244.255.31.64/27244.255.31.65 to 244.255.31.94244.255.31.9530
252244.255.31.96/27244.255.31.97 to 244.255.31.126244.255.31.12730
253244.255.31.128/27244.255.31.129 to 244.255.31.158244.255.31.15930
254244.255.31.160/27244.255.31.161 to 244.255.31.190244.255.31.19130
255244.255.31.192/27244.255.31.193 to 244.255.31.222244.255.31.22330
256244.255.31.224/27244.255.31.225 to 244.255.31.254244.255.31.25530

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.